Self-starter for engines



July 11, 19390 B. H. MCMANEUS S ELFSTARTER FOR ENGINES Filed March 29,1938 r a I, III

Patented July 11, 1939 UNITED STATES PATENT OFF-ICE or of one-half toGeorge T.

Sebring, Fla.

.Whitehouse,

Application March 29, 1938, Serial No. 198,766

3 Claims.

This invention relates to self-starters for engines and moreparticularly to a drive connection between the conventional electricstarting motor and the flywheel of an internal combustion engine.

An object of the invention is to provide a drive means from the startingmotor shaft to the engine flywheel of a Bendix type starting mechanismwhich will insure starting of the engine under all conditions.

A further object of the invention is to so construct a motor drivehaving a resilient coupling interposed between the motor and engine tothereby lessen the initial shock or jar when the parts of the drive areengaged.

Another object is to provide a direct or positive engagement of thestarter pinion regardless of the resilient coupling so that in the eventof breakage or weakening of the cushioning interposed in the couplingthe starting motor will always rotate the starting pinion to engage theflywheel.

It has been customary in the prior art to utilize a coil spring forconnecting the starting motor shaft and the screw threaded sleeve onwhich the starting pinion rotates and travels. In the event that thisspring weakens or is broken there is no connection between the startingmotor shaft and the pinion and unless a hand crank is available theoperator is unable to start the engine.

In the drawing:

Fig. 1 is a partial side elevation of the drive connection between thestarting motor and the engine flywheel, the resilient connection beingshown partly in cross section;

Fig. 2 is a vertical cross section taken on line 22 of Fig. 1;

Fig. 3 is an enlarged fragmental view illustrating the positive drivemeans between the pinion sleeve and the driving head secured to thestarting motor shaft;

Fig. 4 is a vertical cross section of a modified drive coupling as wouldbe taken on line l-4 of Fig. 2.

In the drawing letter M denotes a conventional electric starter motorhaving an extended shaft l to which is bolted a flanged driving head orplate 2. A pair of spaced longitudinally extending drive lugs or prongs3 are formed integraliy with or are welded to the face of thedriving'head 2 and lie parallel with the shaft 5. It is preferable togive the prongs a bevelled cross section, as illustrated.

' An elongated sleeve member 4 having an externally screw threadedportion 5 is loosely mounted on shaft i, and retained thereon bycircular plate 6 threaded to the outer end of the l and affixed theretoby pin 1. The portion 8 of the sleeve 4 is thickened and machined toform a pair of spaced driven lugs or prongs l0, similar to and adaptedto cooperate with driving prongs 3. An enlarged diameter cup shapedflange l I is welded or otherwise secured to the sleeve portion 8 andconcentrically overlies the driven lugs Ill. The flange H also extendsover and encompasses the driving head or plate 2.

A pinion I2 is threaded over the portion'5 of the sleeve and rotatesfreely thereon, its movement being confined between the edge of sleeveportion t and end plate t. The pinion carries teeth II which mesh withcorresponding teeth ll cut on the flywheel of an engine E.

Referring again to the driving and driven lugs or prongs 3 and it (seeFig. 2), it will be seen that both sets of prongs, together with thedriving head 2 and cup plate l l are connected through the medium of afiat concentrically wound coil spring it. To insure a firm contact ofthe prongs, one of the lugs It may be slightly thinner in section thanthe other to compensate for the thickness of the spring 85. i

The inner end of the spring I 5 is bent inwardly at it and hooked overone of the driving prongs 3, while the outer end of the spring is passedthrough a slit l'l cut in the edge of the flange it. If desired, a setscrew it may be tapped into the flange for holding the outer end of thespring. A diametrically opposed cut Ha is also provided so that theapparatus may be used on either a right or left hand starter drive.

In operation, rotation of shaft l of electric motor M moves the drivingprongs 3 clockwise, carrying with them the free end E6 of the spring l5.Tension of the spring is immediately created and tends to slightlycushion or snub the rotation of the shaft. This braking action is ofsmall magnitude and is only suflicient to prevent jar or shock to thedevice when the prongs 3 strike the driven prongs i0 aflixed to thesleeve 4.

As actual contact occurs, the driving prongs move the driven prongs torotate the sleeve ii and thus feed the pinion l3 outwardly along thescrew threads 5. When the pinion strikes end nut E, its movement isarrested and it has meshed with the teeth i l on the periphery of theflywheel of engine E. Continued rotation of shaft i will thus rotate theflywheel and start the engine. As the engine picks up under its ownpower, the starter motor is stopped and the combined kick back of theflywheel teeth, together with the released tension of the spring H,feeds the pinion I I3 back to its starting point. Incidentally, it 'iscustomary to weight a portion of the pinion to keep it in position.

Thus all of the advantages of the conventional starter drive are screwedtogether with a positive engagement of the driving and driven elements,and even though the resilient coupling weakens or breaks, the operatoris believed to engage the starter pinion to start his engine. Byinterposing the coiled tension spring l4 within the compartment formedby plate 2 and cup flange l l, and because the spring acts as acushioning means only and not as a driving connection, its useful lifeis increased many fold. The noise incident to starting of the car isvastly decreased as there is no violent contacting of moving parts withattendant shock to the mechanism.

Fig. 4 is a modification of the starter drive wherein a slightlydifferent form of spring. is utilized, the remainder of the drivemechanism being identical to that previously described. Instead of thefiat torsional spring M of the first form of the invention a coiledtension spring 20 is substituted therefor. The bent ends 2| of spring 20are retained in openings 22 formed in the driving head 2 and flangeddisc H. The action of the coil spring 20 is similar to the action ofspring M, in that the rotation of the motor shaft I takes up the initialtension of the spring and cushions the contact of the lugs 3 and If!before applying torque to the sleeve 4. The position of spring 20 isadjustable to provide for right or left hand rotation of the startershaft by merely reversing its position.

What I claim is:

1. An engine starter comprising a prime mover shaft having a drivinghead thereon, an externally threaded driven shaft sleeved on said primemover shaft and adapted to screw threadedly engage a starter pinion, ahousing carried on one end of said driven shaft adjacent said head,fingers projecting from said head and said driven shaft within saidhousing and in overlapping relationship.

2. An engine starter comprising a prime mover shaft having a drivinghead thereon, an exter nally threaded driven shaft sleeved on said pri emover shaft and adapted to screw threadedy engage a starter pinion, ahousing carried on one end of said driven shaft adjacent said head,fingers projecting from said head and said driven shaft Within saidhousing and in overlapping relationship, and resilient means connectingsaid head and driven shaft for permitting relative rotationtherebetweenf 3. An engine starter comprising a prime mover shaft havinga driving head thereon, an externally threaded driven shaft sleeved onsaid prime mover shaft and adapted to screw threadedly engage a starterpinion, a housing carried on one end of said driven shaft adjacent saidhead, fingers projecting from said head and said driven shaft withinsaid housing and in overlapping relationship, and resilient meansconnecting said head and driven shaft for permitting relative rotationtherebetween, said resilient means comprising a torsion spring havingone end secured to said housing and its opposite end to a finger on saiddriven shaft.

BENNETT HAYES MCMANEUS.

